Hello, don't know if anyone here can help me or not, but I have a mercedes slk230. I had a hydraulic leak problem with the locking/unlocking roof cylinder. I took it to a local mechanic. They hooked up the hydraulic lines backwards to the pump. The corresponding check valves in my pump were damaged and they say crossing lines would not damage the valves. I
believe they were cause the roof was operating fine even while leaking fluid. Can anyone tell me the effects of inverting hydraulic lines to the pump?

Sounds like an unfortunate situation, sorry to hear.

Hydraulics in general operate with one basic principal: Apply pressure to one side of a piston while venting the opposite side to a resevoir. The fluid needs to be directed and redirected as desgined to operate correctly.

In my oppinion I do not see how reversing the lines could have any impact on any other device in the system. The only thing that would occur is the cylinder that the lines were crossed on would work in reverse. It may be possible for a damaged check valve to create other problems, cylinder failure may be one those problems.

It may be helpful to review your owners manual. I believe you will find some important facts regarding "Pump" operations under certain conditions. Unpleasant and unwanted things can/will occur "IF and/or WHEN" certain procedures are not followed.

but mercedes dealer told me that inverting the lines to the pump caused the valves to function incorrectly thus damaging them. Out of all the check valves in the pump, the only 2 that are bad are the ones where the lines were inverted into. I only had a hydraulic leak. If these valves were bad previous to the leak, wouldn't that have prevented fluid from reaching the cylinder that leaked in the first place?

downtick

one other thing, nothing else in the pump was bad, no cylinder. Just the 2 check valves in question. Mercedes tells me inverting the lines damaged the valves. The valves did not damage anything else cause everything else in the pump functions as designed.

If the lines to one cylinder were mistakenly crossed (in-out) one can expect that cylinder to operate in reverse (out-in). If 2 lines from two different cylinders were crossed than maybe some damage can be incurred.

I have studied the hydraulic diagram and in my opinion I cannot see how reversing the lines to a single cylinder can cause the damage you are describing.

A question I might ask is "when the fluid leak was discovered did someone by-pass that cylinder at the pump by disconnecting the lines and capping the ports, possibly bridging them to each other?" Second "if there was an obvious fluid leak than why would anyone be inclined to disconnect lines at the pump?" I would be inclined to believe that if the fluid circuit was by-passed so as to avoid fluid loss, than the resulting damage may have been caused by that action rather than crossing the lines.

all i know is that they did diagnostics, it clearly states it on their invoice to me. They called me and informed me of the problems they found. I gave them the ok to fix it. Upon completion, roof would not operate. I take it to mercedes, on their invoice they do diagnostics, they find 3 error codes and 7 problems with hydraulics. If these problems existed prior, why didn't my local mechanic find them when they ran diagnostics? It clearly states that they diagnosed the problem on the inovice. Could it possibly be that these problems did not exist prior, that's why they were not discovered????? Hmmmmm

There is a significant difference in the diagnostics between the aftermarket and the factory due in part to the diagnostic equipment being utilized. Unless the independent repair center possesses an SDS/DAS system tester a complete system diagnosis on any late model MB, at best will be extremely challenging. A dealer technician may have 300 pieces of information that are accessible/viewable with the SDS/DAS for that system. An aftermarket scan tool may only provide a fraction of that information, say 100. Without access to the other 200 pieces of data how effective will the diagnosis be???

I am going to go out on a limb and speculate that the core issue is "someone is going to pay for the pump?" Can all the damage be attributed to one event? If so, which event? I do not believe I can provide you with the reassurance that crossing two lines to a single cylinder caused the pump to fail.

I am unable to connect those dots ……………..the way I see it, the cylinder would simply work in reverse.

don't know the equipment they have to do their diagnostics, but being they advertise they service mercedes, they do have some kind of equipment. In any event, I haven't even mentioned the other problems that they did while installing the new cylinder. One being, when they put the latches back in place, they did not correclty adjust them thus breaking a microswitch on one of the 2 latches. Mercedes states the roof would not unlatch nor funtion with a microswitch broken. Could these have really been pre existing as well? How could I have put my roof down if the switch was broken and the latches would not allow the roof to release? They put these latches back on when they put the cylinder back in its place. They really did a number on my car!

Downtick

With most late model MB if the service center is not equipped with an SDS/DAS system tester more often than not diagnostics can, or will, be a crap shoot.

I strongly encourage MB owners with 1998 and newer cars to seek out qualified refferals prior to addressing any diagnostic and service need.